Research On Probe Correction Of Near-field Measurement Based On The Three-antenna Extrapolation Technique

Since the appearance of near-field measurement technology in the time domain from 1994,it has undergone theoretical advancement,theoretical development,and test verification.However,due to various error terms in time-domain near-field measurements,there is currently a lack of systematic research on these error terms.Therefore,the near-field measurement method in the time domain has not been able to enter the actual engineering application stage.The introduction of the probe in the time domain measurement,which introduces a number of error terms,how to correct the error term introduced by the probe,has a crucial role in the practical application of the time domain near field measurement.The three-antenna extrapolation method is an internationally recognized antenna measurement technology with the lowest measurement accuracy and the smallest error.The idea of this measurement method is to extrapolate the antenna to be measured by sequentially measuring three antennas with unknown parameters.Obtain antenna gains for multiple groups of distances,and then use the data fitting in the later period to remove the mutual coupling between the antennas to obtain the absolute gain of the antenna at infinity distance.In this paper,by combining the three-antenna extrapolation measurement method with probe correction,the probe is measured to obtain the relevant precise parameters of the probe,and the probe is modified to obtain the respective correction results in the time-frequency domain,and the resulting correction is obtained.The results were verified by simulation.The main work of this article includes:The first history of antenna measurement development and various measurement techniques were briefly introduced.The error terms in the frequency-domain and timedomain near-field measurements were listed.The significance of probe correction for near-field measurements was illustrated.Second,based on the principle of plane wave scattering matrix,the coupling equation and power series expansion between two antenna systems are deduced.The traditional three-antenna method,the traditional three-antenna extrapolation method and a simple three-antenna extrapolation method are performed.Derivation instructions.The extrapolation device of China's Institute of Quantitative Sciences was described and the measured data was given.The data given by British NPL was compared.The influence of the third pair of probes on the antenna to be measured in the near-field measurement is described.The factors that cause the measurement error of the probe are introduced.The principle of probe modification based on the extrapolation method is given and the probe is defined to be modified in the frequency domain.Time domain corrected transfer function.Fourthly,based on the CST software simulation,the rectangular waveguide probe is modified in the frequency domain and time domain.The obtained time domain correction results are verified,and the resulting errors are analyzed and explained.The fifth article summarizes this article and explains the direction of future research.